Republicans have slammed Homeland Security for releasing 2,228 detainees. But the real question is why most of them were being held at all.

In recent weeks, Republican lawmakers have slammed the Department of Homeland Security for releasing 2,228 immigrants from detention centers around the country, questioning, among other things, whether murderers, rapists and drug traffickers were among those set free.

But while it is unclear whether Homeland Security's decision to release the detainees was prompted by the austerity requirements of sequestration or by political theatrics, what is certain is that those who were released didn't pose an egregious threat to public safety. More than 70% of those detainees have no criminal history, according to federal officials. The rest — with the exception of 10 immigrants — had only misdemeanor convictions, including shoplifting and minor drug possession.

Frankly, instead of trying to score political points by exaggerating the dangers, lawmakers ought to have asked why these nonviolent immigrants were being held in the first place, when cheaper and equally effective alternatives to detention exist.

The immigrant detention system on any given day holds about 34,000 noncitizens awaiting deportation hearings. The Obama administration has repeatedly said that it wants to focus detention and deportation efforts on the "worst of the worst." Surely, visa over-stayers, asylum seekers and shoplifters who are believed to be neither flight risks nor safety risks do not fit that profile.

Moreover, incarcerating nonviolent immigrants who face civil deportation cases is a strikingly inefficient way to spend tax dollars. It costs an average of $122 to $164 a day to detain immigrants in federal custody. In contrast, alternatives such as supervised release or electronic monitoring carry an average price tag of about $14 a day. More than 95% of immigrants in such programs showed up for their final court hearing, according to Human Rights First.

No one disputes that immigrants who commit violent crimes should be detained. But locking up those with no criminal history is a waste of both money and resources.